Design, Synthesis and Optical Properties of Novel Aggregation Induced Emissive Organic Luminogen.

Abstract

Luminescent materials have attracted special attention in recent decades because of their prospective uses, in mechanical sensors, optical storage, optoelectronics, digital security, etc. Herein, we report design, synthesis, and optical properties of a donor-acceptor-donor (D-A-D) type organic luminogen TPACNTPA with highly electron-rich triphenylamine moiety as a donor and electron-deficient cyano-ethylene moiety as acceptor. The donor-acceptor architecture of such luminogen often leads to a very high conjugation length and is very much beneficial to obtain multi-color luminescence. Here also, a ~ 100 nm red-shift along with blue to yellow emission were obtained by varying the solvent polarity indicating presence of a strong intramolecular charge transfer process in an excited state. Further, the time-resolved PL decay also justified the same as the average lifetime decreased in high polar solvents due to stabilization of the ICT state. Additionally, the higher degree of flexibility and presence of multiple rotatable bonds in the molecular structure lead to a strong aggregation-induced emission above 60% water content in THF solvent. The formed aggregates in higher water content has been characterized by AFM study. Such an interesting property of TPACNTPA can lead the luminogen to be highly emissive in solid-state and can be used to fabricate OLED and other display devices.